Re: [RFC 7/8] Enhance ramfs to support higher order pages

[William Lee Irwin III <wli@holomorphy.com>]

On Fri, 20 Apr 2007, William Lee Irwin III wrote:
>> The core VM can do that but the hugetlb architectural code can't fall
>> back to smaller page sizes. It also should not be put into a situation
>> where it needs to do so given the semantics it must honor.

On Fri, Apr 20, 2007 at 10:15:00AM -0700, Christoph Lameter wrote:
> Wel we could potentially add a handle_pmd_fault to the vm...?

Unconscionably foul. I guess x86-uber-alles pagetables in the core vm
is the Linux way, though.


On Fri, 20 Apr 2007, William Lee Irwin III wrote:
>> Also, the final assertion is inaccurate. Fault handlers must instantiate
>> pages of order mapping->order when faulting in a page of a file with
>> a given pagecache size. The semantics of faulting and mmap()'ing are

On Fri, Apr 20, 2007 at 10:15:00AM -0700, Christoph Lameter wrote:
> Why? I agree that the page state of the higher order page must be updated 
> consistently but one can use a pte to map a 4k chunk of a higher 
> order page.

Probably just terminological disagreement here. I was referring to
allocating the higher-order page from the fault path here, not mapping
it or a piece of it with a user pte.


-- wli